Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy from wind using known foil principles and transmit the kinetic energy through rotational energy to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
Wind turbine rotor blades generally include a body shell formed by two shell halves of a composite laminate material. The shell halves are generally manufactured using molding processes and then coupled together along the corresponding edges of the rotor blade. In general, the body shell is relatively lightweight and has structural properties (e.g., stiffness, buckling resistance and strength) which are not configured to withstand the bending moments and other loads exerted on the rotor blade during operation. In addition, wind turbine blades are becoming increasingly longer in order to produce more power. As a result, the blades must be stiffer and thus heavier so as to mitigate loads on the rotor.
To increase the stiffness, buckling resistance, and/or strength of the rotor blade, the body shell is typically reinforced using one or more structural components (e.g. opposing spar caps with a shear web configured therebetween) that engage the inner surfaces of the shell halves. For example, as shown in FIG. 1, a cross-sectional view of a conventional rotor blade 1 is illustrated. As shown, the shear web 4 extends between the opposing spar caps 2, 3 so as to reinforce the rotor blade 1. Wind turbine spar caps are typically constructed of fiber laminate composites, which can be difficult to control, defect prone, and/or highly labor intensive due to handling of the dry and pre-preg fabrics and the challenges of infusing large laminated structures.
As such, certain spar caps can be constructed of pre-fabricated, pre-cured (i.e. pultruded) composites that can be produced in thicker sections, and are less susceptible to defects. Accordingly, the pultruded composites can eliminate various concerns and challenges associated with using dry fabric alone. As used herein, the terms “pultruded composites,” “pultrusions,” “pultruded members” or similar generally encompass reinforced materials (e.g. fibers or woven or braided strands) that are impregnated with a resin and pulled through a stationary die such that the resin cures or undergoes polymerization through added heat or other curing methods. As such, the process of manufacturing pultruded composites is typically characterized by a continuous process of composite materials that produces composite parts having a constant cross-section. Thus, as shown in FIG. 1, a plurality of pultrusions, e.g. pultruded plates 5, can be arranged together to form the spar caps 2, 3 and/or various other rotor blade components.
More specifically, as shown in FIG. 2, one example pultruded composite 5 that may be utilized in a spar cap 2, 3 of the rotor blade 1 is illustrated, with the pultruded composite 5 having a solid board configuration. Such a configuration, however, is not easily contourable or formable to the blade surface of the rotor blade 1. Thus, as shown in FIG. 3, another example pultruded composite 5 that may be utilized in a spar cap 2, 3 of the rotor blade 1 is illustrated, having a plurality of pultrusions 6 secured together via a skin layer 7. Though the pultruded composite 5 of FIG. 3 may be more contourable to the blade surface of the rotor blade 1 than the composite 5 of FIG. 2, such a configuration can be time-consuming and expensive to manufacture.
Accordingly, the art is continuously seeking new and improved methods of manufacturing rotor blade components, such as the spar caps, using pre-cured composites. Thus, the present disclosure is directed to methods of manufacturing rotor blade components with pultruded composites having a toothed configuration.